Trailer hitch



April 1, 1941,

G. B. SCHOENROCK TRAILER HITCH F'led March 1, 1940 2 Sheets-Sheet 2,

fa fdp Y NVENTOR @o2-geg taen/acff ATTORNEY/7 Patented Apr. 1, 1941 "UNITED STATES raronlie V2,237,166 'raAmEnnrron George B; Schoenrock, Detroit, .Mich. t Application March 1, 1940, Serial`No.'321,648

6 Claims. (Cl. 28m-33.9)

This invention relates to .trailer hitches of the type employed for Atowing house trailers `and light commercial trailers and :in particular to 'trailer hitches whichistabilize thefriding qualities of both the tow car andthe trailer.

The primary object of th'einvention is to prowde a trailer hitch which measurably improves the riding qualities of the '.tow car-trailer combination by minimizing the vertical whip of the trailer with respect to the tow car land by reducing 'the spring-"action or bounce of the rear end of the ytow car on its springs when the tow car-trailer combination i's driven .over rough or lbumpy roads at :relatively high speeds.'

Another .object of the 'invention is to provide a trailer hitch which reduces to .a minimum the tendency of the front end of the `tow car -of a toWcar-trailer combination to lift up when `going over bumps or dishes in the road.

. Another object lof the invention is to provide a trailer hitch pivoted `.verticallyfat a :point forward ofthe rear axle of the tow car of a `tow car-'trailer combination includ-ing .means ffo'r stabilizing the vertical pivoting or vertical whip of the `trail-er and Itrailer hitch with respect to thetow car.

.Another `object `of fthe invention is to provide a trailer hitch which distributes the weight of the trailer to all `four wheels of 'the ytow car `and vwhich dam-pens out rshocks Vtransferred to the frame -of the tow car caused by the vertical whip of the trailer with :respect tothe tow lcar when the ftow car-trailer combination kis driven over rough roads.

Still another object Yof the 'invention is to provide a trailer hitch which presents a neat appearance and which serves as a bumper support or bumper when .a trailer is .notcoupled thereto.

Other objects of the invention 'will become apparent by reference to the .following detailed description taken connection with vthe accompanyingdrawings, -i-n which:

A Fig. .l isa more or less diagrammatic plan view of a towjcar and trailer combination employing 'a 4trailer hitch Vembodying the invention as the couplingmeans therebetween.

Fig. `2 is an enlarged -fragmentary plan view showing Yinmore detail the trailer hitch construction disclosed -in Fig.. l.

Fig. .3 .is aside elevational view :of the construction disclosed in Fig. 2.

Fig. 4 vis .an .enlarged cross sectional view .taken on Athe line 4-4 of Fig. 3 showing the trailer hitch shock absorbing and .stabilizing means preferably employed.

Fig. 5 is 'an enlarged cross sectional view taken on the Vline `5--5 of Fig. 3 showingthe stop means preferably employed to limit lthe vertical -pivotal movement .of the trailer hitch with respect kto the frame of the tow car.

Figs.v 6`and 7 are fragmentary views similar to Fig. 3, each showing an alternate location of the stabilizing `and fshock absorbing means with respect to the pivotal mounting of the trailer hitch on the frame of the tow car.

Fig. 'discloses an alternate embodiment of the trailer hitch invention disclosed in Figs. 1 to '7 inclusive preferably employed for commercial trailers or very heavy 'house trailers.

Fig'. 9 is a side elevational view of the construction disclosedin Fig. 8.

. means of a trailer hitch 22 embodying the invention, the tongue member 23 ofthe trailer 2| being connected to the trailer hitch 22 by a ball and socket joint 24. The said trailer hitch 22 is U-shaped v'and -is vertically pivote'd to the main frame -2'5 of the tow car -20 on lhorizontally `disposed pivots '2S preferably located forward of the rear- 4axle 21 of the said 'tow'car 20.

The tow `'car 2l) rmay be apa'ssenger automobile,y

as indicated, or rit may be a truck or other type `tractor; the trailer 2| ybeing preferably of the type supportedL on Ytwo wheels 23 ymounted on Ya 'socket joint 24 .between the trailer tongue -memtransverse axle '-29 suspended by leaf springs 3l) below the body of the trailer. T-he said transverse trailer a-Xle `29 is vpreferably `located to the rear of the center -of gravity `-of the said trailer 2| whereby to provide a normal ydownward pressure on the .trailer hitch 22 atthe said ball and socket joint .24 preferably employed between the tongue member 2.3 of .the trailer 2| and the said trailer hitch V22. The employment of a ball and ber .2.3 and .the trailer hitch =22 admits of a universal movement between the trailer 2l and the tow car 20 4and prevents undue shock on 'and -distortion of -the trailer hitch 22 under condi-tions of .heavy impact which occurs when traveling lat rather high speeds lover relatively rough or bumpy roads.

l rIlhe vU-.shaped trailer hitch v212 is preferably composed of two vtubular side members 3l formed longitudinally to follow generally the shape of the side members 25D of the main frame 25 of the tow car 25 and a tubular transverse rear member 32 secured across the rear end of the said tubular side members 3| and disposed rearwardly from and in sufficient spaced relationship to the rear transverse frame member 25| of the car 20 to clear the rear end of the body 200 of the said tow car 20. As before mentioned, the said U-shaped trailer hitch 22 is vertically pivoted on the main frame 25 of the tow car 20 on horizontally disposed pivots 26 located at a point forward of the rear axle 21 of the said tow car 20.

A suitable stop 33 is secured on the outside of each side frame member 250 of the main frame 25 of the tow car 20 in such a position as to bev contacted by the side members 3| of the trailer hitch 22 when the said trailer hitch 22 pivots approximately to the downward limit permitted by the hitch stabilizing means 4|) as hereinafter described in detail. Each of the said stops 33 preferably comprise a thimble 34 having a resilient shock absorbing element 35 moulded therearound and are each secured to a main frame side member 255 as indicated in Figs. 2, 3 and 5 directly under and slightly spaced from the normal position of the adjacent tubular side member 3| of the trailer hitch 22 by means of a suitable bolt 36, nut 3'! and lock washer 33; the said bolt 36 extending through the main frame side member 256 and the thimble 34 of the said stop 33.

A trailer hitch stabilizing means 40 is secured to each main frame side member 250 and the tubular side member 3| of the trailer hitch 22 adjacent thereto at a point `spaced either rearwardly or forwardly or both rearwardly and forwardly from the horizontally disposed pivots 26 upon which the trailer hitch 22 pivots vertically with respect to the main frame 25 of the tow car 25, see Figs. 3, 6 and 7. The said trailer hitch stabilizing means 40 serves the function of retarding the free vertical pivoting of the trailer hitch 22 with respect to the main frame 25 of the tow car 20 and at the same time holds the said trailer hitch 22 in a normal or neutral positionv substantially parallel to the main frame 25 of the said tow car 26.

As best shown in Fig. 4. each trailer hitch stabilizing means 4U preferably comprises a bolt 4| telescoped with a tight fit transversely through a trailer hitch tubular side member 3| of the trailer hitch 22 at a point longitudinally spaced from the pivot 26 upon which the said tubular side member 3| is pivoted to the adjacent main frame side member 25|] and extending through an aperture 42 somewhat larger than theV disposed between the resilient element 43 andy the nut 45 prevents loosening of the said nut 45. A spacer washer 41 of suitable thickness and preferably having its central aperture the same diameter as the aperture 42 through the main frame side member 250 is telescoped over the bolt 4| during the installation of the trailer hitch stabilizing means 40 and is positioned between the tubular trailer hitch side member 3| and the adjacent main frame side member 253 to maintain the same in the desired spaced relationship with respect to each other.

The resilient element 43 shown in Fig. 4 comprises a hollow more or less frusto-conical resilient member 48 having a retainer ring 49 around the base thereof which telescopes into the annular center of the rectangular positioning member 44. A heavy grommet 56 through which the bolt 4| of the stabilizing means passes is preferably moulded into the small end of the frustoconical resilient member 48 of the said resilient element 43. Obviously, the tighter the nut 45 of the stabilizing means 4i] is drawn, the less resiliency there is to the resilient element 43 and the less the trailer hitch 22 will pivot about the horizontally disposed pivots 26 when under load from the trailer 2|.

There is considerable resiliency to the tubular side members 3| of the trailer hitch 22. If no anchorage or restraining means such as the stabilizing means 40 were employed, the tubular side members 3| would merely pivot freely with respect to the main side vframe members 250 of the tow car 20 at the horizontally disposed pivots 26. If the trailer hitch 22 was rigidly secured to the side frame members 256 of the main frame 25 of the tow car 26 at the pivots 26 and at the points where the resilient stabilizing means 40 is employed, see Figs. 3, 6 and rI, then the tubular side members 3| of the trailer hitch 22 would have to absorb by the inherent resiliency thereof all of the impact transferred to it by the vertical whip. of the trailer 2| with respect to the tow car 20 when traveling over rough roads at relatively high speeds.

It has been found that it is substantially impossible within practical and economic limits to construct the side members 3| of the trailer hitch 22 sufficiently strong toA stand such impact if rigidly secured to the main frame 25 of the tow carl 20 at points forward with respect to the rearaxle thereof. By employing resilient sta-y bilizing means 40'as hereinbefore describedin detail.; ithas been found that the road shocks from the load of the trailer 2| and the vertical whip therefrom is easily handled by a light economical-tomanufacture and readily installedv trailer hitch 22 as herein disclosed, and, at the same time. the dead weight of the trailer 2| is carried forward of the rear axle 2`| of the said tow car 20. Thus the weight of the trailer'an'dbilizing means 49. Although not shown, :like orother types of stop means may be employed to limit the upward pivoting of the trailer hitch'22 as permitted by the resilient stabilizing means 40. The latter is not necessary in the majority 'of instances because of the fact that the center 'may as indicated :in Fig. L2. VIn ywhich event, it might be necessary toscallop fout'ith'elupper 'centraliportion :'53 .of the .bumper 5I .to .permit :the 'tongue member 23 'of .the trailer .2l .to clear .the .said bumper l. Because of the :neatness and desirable appearance of the trailer hitch 22, and inasmuch as -itlcarries the bumper 5l| normally bracketed 'from .the tow car .20, the trailer .hitch 22 vneed vnot be removed once :it is installedcn a tow car.

Fig. 1'0 shows the Vtongue Tmember 23 of the trailer .2| connected by .means of splice .plates 54 and fbolts 55 to the .socket member 56 .of .the ball and .socket joint 24 preferably `employed to iconnect a trailer 2l to a trailer hitch 22 embodying theinvention. The ball member 5.1 ofthe said ball .and socket .joint 24 is preferably constructed 'with a .flange 58 and a stem 59 which eX- tends through the ktop of the tubular transverse rear member 32 of the trailer hitch 22 and is welded thereto as indicated .by the numerall 60 in Fig. 10. The socket member 56 is preferably formed at 550 as indicated in the drawings to accommodate .the ball member 51 and is provided with a suitable ball retaining member 6I keyed on a transverse shaft 62. A compression spring 63 is employed lto constantly `urge the said ball `retaining member 6l against the Vsaid ball.

member 51. The ball and socket connection between the trailer 2l and the trailer hitch 22 is accomplished by simply placing the socket member 56 on the trailer tongue 23 in registry over the ball member on the trailer hitch 22. The retaining member 5| .maintains the ball and .socket joint intact until the release lever 64 keyed on the transverse shaft 62 is moved in the direction indicated by the arrow .65 in Fig. 10, whereupon the trailer tongue 23 may be lifted freely from the trailer hitch .22.

The alternate embodiment of the invention z designated by the numeral 22!) in Figs. 8 and 9 is similar in every respect to 'the embodiment of the invention disclosed in Figs. 1 to 7 inclusive, except that the rear bumper 5l has been omitted and a transversely disposed whip relief member 65 has been added. The whip reliefmember 65 is located in spaced relationship to the rear of the tubular transverse rear member 32 of the trailer hitch 220 and sufciently above the said transverse rear member 32 to permit the tongue member 23 of the trailer 2| connected to the said transverse rear member 32 to pass therebelow, see Fig. 9. The said whip relief member 65 is preferably securely bolted to the top of the rear end of the tubular side members 3| of the trailer hitch 223. A ball and socket joint 24 is preferably employed to accomplish the connection between the tongue member 23 of the trailer 2|0 and the trailer hitch 22D on the tow car 20, the ball member of the said ball and socket joint 24 being secured to the top of the tubular transverse rear member 32 of the trailer hitch 220.

The trailer hitch 220 disclosed in Figs. 8 and 9 functions similarly to the trailer hitch 22 disclosed in Figs. 1 to '7 inclusive, except that the whip relief member 65 reduces the tendency for the trailer hitch 223 to pivot about its horizontally disposed pivots 25 by establishing a lever action between the trailer 2li) and the trailer hitch 220 wherein the end of the tongue member 23 bears on top of the tubular transverse member 32 of the said trailer hitch 220 and the bottom of the whip relief member 65 bears on top of the tongue member 23 at its widened portioni23, '-.all .limiting .the downward vertical whippf ith'e trailer 1211i Iwithfrespect toLthe .towl

car .20. rand thereby .reducing the impact Awhich theitubular :side members 3210i the .trailer hitch andthe .hitch rstabilizing means 40 must absorb. It islpreferred .to use the trailer hitch 220 disclosed'finEigs. 8-.and:9 where the size, weight and balance'of the vtrailer .2"I disclosed in Figs. 1 to '.71inclusiveis such that the trailer hitch 22 'would 11. A trailer hitch comprising a pair `of side members formed to follow generally the 'shape of the frame of .a tow car extending .rearwardly l from said tow car and :a 'transverse member secured Ithereacross, horizontal .pivot means .on the v frame of said tow lcar located forward of the rear axle thereof engaging the side membersi'of said trailer` hitch pivotally connecting the said trailer hitch `to the frame 'of .the tow car, means spaced forwardly and rearwardly from saidpivot means engaging the side `members of the said trailer hitch and the frame members of the said tow `car resiliently ysupporting said trailer .hitch in a substantially horizontal position, and stop means von `the frame of the tow car 'for preventing excessive deflection of the said side members when the trailer hitch pivots downward with :respect 'to the frame of the 1said tow'car, and means forfconnecting a trailer to 'said 'trailer hitch per-` mitting universal movement therebetween.

2..A `trailer hitch comprising a pair `of side members 'formed 'tofollow :generally the shape of the frame of a tow car extending rearwardly from said tow car and a pair of longitudinally spaced transverse members secured thereacross, the rearmost transverse member being spaced above the other, horizontal pivot means on the frame of said tow car located-forward of the rear axle thereof engaging the side members of saidl trailer hitch pivotally connectingthe said trailer hitch to the frame of the tow car, means spaced forwardly and rearwardly from said pivct means engaging the side members ofthe said trailer hitch and the frame members of the said tow car resiliently supporting said trailer hitch in a substantially horizonal position, and means for connecting a trailer to said trailer hitch permitting universal movement therebetween extending below the said rearmost transverse member and located en top the other.

3. A trailer hitch comprising a pair of side i members formed to follow generally the shape of the frame of a tow car extending rearwardly from said tow car and a pair of longitudinally spaced transverse members secured thereacross, the rearmost transverse member being spaced above the other, horizontal pivot'means on the frame of said tow car located forward of the rear axle thereof engaging the side members of said trailer hitch pivotally connecting the said` trailer hitch to the frame of the tow car, means spaced forwardly and rearwardly from said pivot and means engaging the side members of the said trailer hitch and the frame members. of the said tow car resiliently supporting said trailer hitch in a substantially horizontal position, the said means for resiliently supporting said trailer hitch in a substantially horizontal position being adapted to serve as stop means against the frame of the tow car for relieving said resilient means of` excessive deflection-when the trailer hitch pivots downward with respect to the frame of theisaid tow car, and means for connecting a trailer to said trailer hitch permitting universal movement therebetween extending below the said rearmost transverse member and located on top the other.

4. A trailer hitch comprising a pair of side members formed to follow generally the shape of the frame of a towcar extending rearwardly from said tow car and a transverse member secured thereacross,'horizontal pivot means on the frame of said tow car located forward of the rear axle thereof engaging the side members of said trailer hitch pivotally connecting the said trailer hitch to the frame of the tow car, and means spaced forwardly and rearwardly from said pivot means engaging the side members of the said trailer hitch and the frame members of the said tow car resiliently supporting said trailer hitch in a substantially horizontal position, the said means for resiliently supporting said trailer hitch in a substantially horizontal position being adapted to serve as stop means against the frame of the' tow car for relieving said resilient means of excessive vdeflection when the trailer hitch pivots downward with respect to the frame of the said tow car, and means for connecting a trailer to said trailer hitchpermitting universal movement therebetween, the said trailer hitch serving as a permanent bumper support for the rear bumper of said tow car.

5. A trailer hitchv comprising a pair of side members formed to follow generally the shape of the frame of a tow car extending rearwardly from said tow car and a transverse member secured thereacross, horizontal pivot means on the frame of said tow car located forward of the rear axle thereof engagingthe side members of said trailer hitch pivotally connecting the said trailer hitch to the frame of thetow car, means spaced longitudinally of said pivot means engaging the side members of the said trailer hitch and the frame members of the said tow car resiliently supporting said trailer hitch in a substantially horizontal position, and stop means on the frame of the tow car for preventing excessive deflection of the said side members when the trailer hitch pivots downward with respect to the frame of the said tow car, and means for connecting a trailer to said trailer hitch permitting universal movement therebetween.

'6. A trailer hitch comprising a pair of side members formed to follow generally the shape of.

the frame of a tow car extending rearwardly from saidtow car and a transverse member secured thereacross, horizontal pivot means on the frame of said towxcar located forwardof the rear axle thereof engaging the side members of said trailer hitch pivotally connecting the said trailer hitch to the frame of the tow car, and means spaced longitudinally of said pivot means engag-v ing the side members of the saidvtrailer hitch and the frame members of the said tow car resiliently supporting said trailer hitch in a substantially horizontal position, the said means for resiliently supporting said trailer hitch in a substantially horizontal position being adapted to serve as stop means against the frame of the tow car for relieving said resilient means of excessive deflection when the trailer hitch pivots downwardwith respect to the frame of the said tow car, and means for connecting a trailer to 'said trailer hitch permitting universal movement therebetween, the said trailer hitch serving as a permanent bumper support for the rear bumper of said tow car.

GEORGE B. SCHOENROCK. 

